Dell PowerEdge R740 EMC NVDIMM-N Persistent Memory User Guide - Page 46

RHEL 7.6 features, Namespace creation

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Create directory /mnt/md0 /mnt/md1 /mnt/md2 /mnt/md5 /mnt/md6. $ mkdir -p /mnt/md0 Create RAID 0 $ mdadm --create --verbose /dev/md0 --level=0 --raid-devices=6 /dev/pmem0 /dev/pmem1 /dev/ pmem2 /dev/pmem3 /dev/pmem4 /dev/pmem5 $ cat /proc/mdstat $ mkfs.xfs /dev/md0 $ mount /dev/md0 /mnt/md0 $ lsblk Before you unmount the device, Read/Write data into /mnt/md0 $ umount /dev/md0 $ mdadm --stop /dev/md0 $ mdadm --zero-superblock /dev/pmem0 /dev/pmem1 /dev/pmem2 /dev/pmem3 /dev/pmem4 /dev/pmem5 $ lsblk Creating RAID 1 is similar as above $ mdadm --create --verbose /dev/md1 --level=1 --raid-devices=6 /dev/pmem0 /dev/pmem1 /dev/ pmem2 /dev/pmem3 /dev/pmem4 /dev/pmem5 $ cat /proc/mdstat $ mkfs.xfs /dev/md1 $ mount /dev/md1 /mnt/md1 $ lsblk Before unmounting the device, Read/Write data into /mnt/md1 $ umount /dev/md1 $ mdadm --stop /dev/md1 $ mdadm --zero-superblock /dev/pmem0 /dev/pmem1 /dev/pmem2 /dev/pmem3 /dev/pmem4 /dev/pmem5 $ lsblk RAID 5/5/6/10 Volumes can be created in a similar way. RHEL 7.6 features Namespace creation Starting from RHEL 7.6, ndctl utility is available natively. NVDIMM-N modules that have FW 9324 are not visible in the OS as this firmware has label support. In other words, namespaces do not get enumerated automatically and using ndctl, namespaces have to be created first before mounting a file system and accessing them. NOTE: It is also recommended that an OS patch is installed first to ensure proper functionality of the ndctl utility for creating namespaces. This patch can be downloaded here https://access.redhat.com/solutions/3920221. Run through the commands below as a super user to create /dev/pmem devices. To display DIMM list run: • $ ndctl list -D Run command below to create namespaces. This command if used as is by default creates /dev/pmem devices. In order to create namespaces in other modes, refer to the link https://www.mankier.com/1/ndctl-create-namespace This command should be run as many times as the number of NVDIMM-N modules plugged into the system. • $ ndctl create-namespace For more information on how to use ndctl utility refer to the users guide here https://docs.pmem.io/ndctl-users-guide 46 Linux

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Create directory /mnt/md0 /mnt/md1 /mnt/md2 /mnt/md5 /mnt/md6.
$ mkdir -p /mnt/md0
Create RAID 0
$ mdadm --create --verbose /dev/md0 --level=0 --raid-devices=6 /dev/pmem0 /dev/pmem1 /dev/
pmem2 /dev/pmem3 /dev/pmem4 /dev/pmem5
$ cat /proc/mdstat
$ mkfs.xfs /dev/md0
$ mount /dev/md0 /mnt/md0
$ lsblk
Before you unmount the device, Read/Write data into /mnt/md0
$ umount /dev/md0
$ mdadm --stop /dev/md0
$ mdadm --zero-superblock /dev/pmem0 /dev/pmem1 /dev/pmem2 /dev/pmem3 /dev/pmem4 /dev/pmem5
$ lsblk
Creating RAID 1 is similar as above
$ mdadm --create --verbose /dev/md1 --level=1 --raid-devices=6 /dev/pmem0 /dev/pmem1 /dev/
pmem2 /dev/pmem3 /dev/pmem4 /dev/pmem5
$ cat /proc/mdstat
$ mkfs.xfs /dev/md1
$ mount /dev/md1 /mnt/md1
$ lsblk
Before unmounting the device, Read/Write data into /mnt/md1
$ umount /dev/md1
$ mdadm --stop /dev/md1
$ mdadm --zero-superblock /dev/pmem0 /dev/pmem1 /dev/pmem2 /dev/pmem3 /dev/pmem4 /dev/pmem5
$ lsblk
RAID 5/5/6/10 Volumes can be created in a similar way.
RHEL 7.6 features
Namespace creation
Starting from RHEL 7.6, ndctl utility is available natively.
NVDIMM-N modules that have FW 9324 are not visible in the OS as this firmware has label support. In other words, namespaces do not
get enumerated automatically and using ndctl, namespaces have to be created first before mounting a file system and accessing them.
NOTE:
It is also recommended that an OS patch is installed first to ensure proper functionality of the ndctl utility for
creating namespaces. This patch can be downloaded here
.
Run through the commands below as a super user to create /dev/pmem devices.
To display DIMM list run:
•
$ ndctl list -D
Run command below to create namespaces. This command if used as is by default creates /dev/pmem devices. In order to create
namespaces in other modes, refer to the link
This command should be run as many times as the number of NVDIMM-N modules plugged into the system.
•
$ ndctl create-namespace
For more information on how to use ndctl utility refer to the users guide here
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Linux